Method and system for interleaving of full rate channels suitable for half duplex operation and statistical multiplexing

ABSTRACT

A time division multiplexed communications method and system in which time is divided into a number of frames and each frame is divided into N data bursts. The method and system further has a first multiplexer by which a half rate channel is formed as a series of bursts that occur periodically every N bursts once per frame, a second multiplexer in which a full rate channel is formed as two half rate channels on consecutive timeslots, and a transmitter transmitting the full rate channel from a first wireless station to a second wireless station. The full rate channel provided by two half rate channels on consecutive timeslots yields a significantly larger resource pool available for assignment of communication traffic. For full rate channels, the interleaving 0246/1357 method that is used by the system is just as good as the known 0123/4567 method when ideal frequency hopping is used, and the 0246/1357 method performs better when non-ideal frequency hopping or no frequency hopping is used.

CROSS REFERENCE

[0001] This application claims priority of Provisional Application Ser.No. 60/175,155, which was filed Jan. 7, 2000.

[0002] This application is related to co-pending applicationsBalachandran 13-18-18-40-1 and Balachandran 11-16-38, which are herebyincorporated by reference.

TECHNICAL FIELD

[0003] The invention relates to relates generally to wirelesscommunication networks and, more particularly, to a method and systemfor efficiently providing voice communications over wireless and/orcellular networks while using full rate channels.

DESCRIPTION OF THE PRIOR ART

[0004] The widespread growing popularity of the Internet has encouragedwireless communication system developers to continually improve the datacommunication capabilities of their systems. In response to this need,various standards bodies have formulated and continue to formulate newthird generation (3G) standards which support higher data rates. Forexample, standards organizations such as the European TelecommunicationsStandards Institute (ETSI), the Association of Radio Industries andBroadcasting (ARIB) and the Telecommunications Industry Association(TIA) are continually developing standards to support faster and moreefficient wireless communications.

[0005] Similarly, the wireless communications industry is oftendeveloping and implementing new wireless transmission protocols whichprovide faster, more robust and more efficient data communications overair interfaces. For example, GSM continues to evolve. In anotherexample, general packet radio service (GPRS) has been developed as apacket-switched upgrade for the well known time division multiple access(TDMA) system. In a further advancement in the art, enhanced GPRS(EGPRS) has also been developed.

[0006] Presently, GSM, GPRS and EGPRS physical layers have the followingcharacteristics: a carrier that consists of two 200 kHz bandwidthsegments of the allocated GSM spectrum, 45 MHz apart, one for thedownlink and one for the uplink; time is divided into frames with amultiframe comprising 52 frames and spans 240 msec.; each frame consistsof 8 time slots; one slot on one carrier is referred to as a GSMchannel; there is a one-to-one correspondence between a slot (numberedj, j=0, . . . 7) on a downlink carrier at frequency (f) and an uplinkslot (numbered j) on the corresponding uplink carrier (f+45 MHz); atransmission in a slot is referred to as a burst; and a block consistsof a predefined set of four bursts on the same slot.

[0007] Radio access bearers are currently being designed in order toprovide real time services in EGPRS Phase II. However, recent approachesrely on using the existing burst based random access channels on theuplink and block based assignment channels on the downlink. Each blockis interleaved and transmitted over 4 bursts (20 msec). However,investigation has shown systems based on 20msec granularity require atleast a 60 msec delay budget. Also, the investigation has showntransmission of assignments to multiple mobile stations within a single20 msec message often is inefficient due to low packing and isincompatible with interference reduction techniques such as smartantennas and power control. As a result, block based assignment channelsaccording to the recent approaches can result in excessive controloverhead and excessive delays for statistical multiplexing of real timetransfers (e.g. voice talkspurts). It is desirable to provide a betteraccess and assignment system and method.

[0008] In order to efficiently use the high capacity of a wireless or acellular data telecommunication system (e.g., GPRS or EGPRS), it is alsodesirable to provide voice and data multiplexing capability as well asstatistical multiplexing of voice users. Currently these cellular datatelecommunication systems are designed to provide primarily non-realtime (delay insensitive) data services. Conversational speech and otherreal time interactive communications are delay sensitive and require thedesign of new control mechanisms to provide fast control channels tomeet the critical delay requirements. Therefore, there is a need toredesign wireless data telecommunication systems to provide such controlcapabilities to make them suitable for multiplexing both non-real-timeservices and real-time services, such as conversational speech.

[0009] Presently under GSM, a mobile user assigned to some channels hasto receive on even bursts in one multi-frame and odd-bursts in the nextmultiframe. Such switching between even and odd bursts is not wellsuited for dynamic assignment of uplink and downlink channels.Therefore, there is a need to redesign wireless data telecommunicationsystems to provide different burst-channel structures that are suited todynamic assignment of uplink and downlink channels. A redesign for halfrate channels and especially for full rate channels. Present full ratechannel structure can be very wasteful of available bandwidth and delaytimes by using the present channel structures and present interleaving.

SUMMARY OF THE INVENTION

[0010] This need is met by the method of the present invention whereinsystems and methods are described that enable efficient and flexiblemultiplexing of both real-time and non-real-time services over full ratechannels of wireless data telecommunication systems.

[0011] Briefly stated in accordance with one aspect of the invention,the aforementioned problems are addressed and an advance in the artachieved by providing a system for communicating using wireless timedivision multiplexed communications in which time is divided into aplurality of frames and each frame is divided into N data bursts. Thissystem includes a first multiplexer defining a half rate channel as aseries of bursts that occur periodically every N bursts once per frame,a second multiplexer for defining a full rate channel as two consecutivehalf rate channels; and a transmitter transmitting the full rate channelfrom a first station to a second station.

[0012] In accordance with a specific aspect of the invention, theaforementioned problems are addressed by providing a system forcommunicating using wireless time division multiplexed communications inwhich time is divided into a plurality of frames and each frame isdivided into N data bursts. This system includes a first multiplexerdefining a half rate channel as a series of bursts that occurperiodically every N bursts once per frame, a second multiplexer fordefining a full rate channel as two consecutive half rate channels; anda transmitter transmitting the full rate channel from a first station toa second station. The system also includes an interleaver whichinterleaves bursts using 0246/1357 interleaving.

[0013] In accordance with another specific aspect of the invention, theaforementioned problems are addressed by providing a method forcommunicating using wireless time division multiplexed communications inwhich time is divided into a plurality of frames and each frame isdivided into N data bursts. This method includes the steps ofinterleaving bursts using a 0246/1357 sequence to provide a plurality ofhalf rate channels, using two consecutive half rate channels of theplurality of half rate channels to provide a full rate channel, andtransmitting the full rate channel made up of the interleaved burstsfrom a first station to a second station.

BRIEF DESCRIPTION OF THE DRAWING

[0014]FIG. 1 is a block diagram of a GERAN system with mobile stationreceiver-transmitters and a central base station receiver-transmitter.

[0015]FIG. 2 illustrates the user plane protocol stack for Pre-GERAN andGERAN systems.

[0016]FIG. 3 illustrates two multiframes each of which is divided intofour channels of various types.

[0017]FIG. 4 illustrates a state diagram for a system in accordance withthe invention.

[0018]FIG. 5 illustrates a state table that is another way of presentingthe information of FIG. 4.

[0019]FIG. 6 illustrates a RT TBF State Diagram in table form.

[0020]FIG. 7 illustrates message and uplink interaction in tabular form.

[0021]FIG. 8 illustrates a summary of downlink signaling and controlmessages in tabular form.

[0022]FIG. 9 illustrates downlink burst message content in tabular form.

[0023]FIG. 10 illustrates uplink burst message content in tabular form.

[0024]FIG. 11 illustrates the temporary block flow of messages between amobile station and a base station of a network using GARAN techniquesduring a start uplink traffic procedure.

[0025]FIG. 12 illustrates the temporary block flow of messages between amobile station and a base station of a network using GERAN techniquesduring an end uplink procedure.

[0026]FIG. 13 illustrates the temporary block flow of messages between amobile station and a base station of a network using GERAN techniquesduring a start downlink procedure.

[0027]FIG. 14 illustrates the temporary block flow of messages between amobile station and a base station of a network using GERAN techniquesduring an end downlink procedure.

[0028]FIG. 15 illustrates the temporary block flow of messages between amobile station and a base station of a network using GERAN techniquesduring a reassign uplink traffic channel procedure.

[0029]FIG. 16 illustrates the temporary block flow of messages between amobile station and a base station of a network using GERAN techniquesduring a reassign downlink traffic channel procedure.

[0030]FIG. 17 illustrates the temporary block flow of messages between amobile station and a base station of a network using GERAN techniquesduring a reassign uplink control channel.

[0031]FIG. 18 illustrates the temporary block flow of messages between amobile station and a base station of a network using GERAN techniquesduring a reassign downlink control channel procedure.

[0032]FIG. 19 illustrates the temporary block flow of messages between amobile station and a base station of a network using GERAN techniquesduring an ET procedure to terminate a TBF.

[0033]FIG. 20 shows a multiframe diagram which is very similar to FIG. 3showing known a GSM half-rate traffic channel structure.

[0034]FIG. 21 illustrates a multiframe diagram very similar to FIG. 20,showing a new GERAN half rate traffic channel structure according to thepresent invention.

[0035]FIG. 22 is a diagram illustrating downlink assignments accordingone communication technique of the invention.

[0036]FIG. 23 is a diagram illustrating downlink assignments accordingto another communication technique of the invention

[0037]FIG. 24 is a diagram illustrating downlink assignments similar toFIG. 22 but with different loading.

[0038]FIG. 25 is a diagram illustrating downlink assignments similar toFIG. 23 but with different loading.

[0039]FIG. 26 is a diagram illustrating half rate bursts on which adownlink talkspurt may start for a Class 1 mobile station.

[0040]FIG. 27 is a diagram illustrating half rate bursts on which adownlink talkspurt may start for a Class 1 mobile station underdifferent conditions than FIG. 26.

[0041]FIG. 28 is a table that shows the speech frame arrivals and playout instants with different interleaving approaches.

[0042]FIG. 29 is a table showing performance of two interleaving schemeswith QPSK modulation.

[0043]FIG. 30 is a diagram illustrating full rate bursts on which adownlink talkspurt may start for a Class 1 mobile station.

[0044]FIG. 31 is a diagram illustrating full rate bursts on which adownlink talkspurt may start for a Class 1 mobile station underdifferent conditions than FIG. 28

DETAILED DESCRIPTION

[0045] Referring now to FIG. 1, a system 1 is shown. System 1 in apreferred embodiment, is a GSM Enhanced-General-Packet-Radio-ServiceRadio Access Network (GERAN) as described herein. GERAN 1 has a centralor base station 12 which has a transmitter, a receiver and an antenna(not shown) as a base station typically has. Base station 12 is part ofthe GERAN 1. GERAN 1 is used to communicate with and carry messagetraffic between a caller on a mobile station 20, and in a preferredembodiment to callers of all kinds and mobile stations, such as mobilestations 20, 30. The base station 12 has a transmitter 13 and a receiver17. Transmitter 13 has multiplexers 14 and 15 that multiplex the speechand/or data traffic to form channels and sub-channels for transmitting.Receiver 17 has corresponding demultiplexers 18 and 19 to demultiplexspeech and/or data received from other stations. With present timedivision multiplexing techniques multiplexers 13 and 14 could be thesame unit, and similarly demultiplexers 18 and 19 could be in the sameunit. To take full advantage of the present invention, mobile stations20 and 30 have compatible multiplexing and demultiplexing functions.Further, the present invention provides new traffic and control channelsthat are completely compatible with beam forming and power controltechniques, enabling their use for all new traffic and control channels.

[0046] The present invention has unidirectional traffic and controlchannels. The benefits of statistical multiplexing are achieved throughthe application of the following principles. All new control and trafficchannels are unidirectional, with independent frequency and slotallocation in the uplink and downlink directions. Available resourcescan be dynamically allocated as necessary to traffic and control channelfunctions. This allows for maximum flexibility in allocation ofavailable resources.

[0047] In previously known GSM, GPRS and EGPRS Phase 1, a multiplexerdefined a channel to consist of one time slot on a 200 kHz carrier atfrequency ƒ for the downlink and a corresponding slot on a 200 kHzcarrier at (ƒ+45 MHz) on the uplink. Breaking this historicalassociation between uplink and downlink channels allows for statisticalmultiplexing of speech, in particular, since the uplink and downlinkresource demands occur independently. Breaking the historicalassociation between uplink and downlink maximizes the resource poolavailable for assignment when new data or speech becomes available fortransmission.

[0048] A primary consideration for any GERAN method and system must bethe impact on half-duplex mobiles, given their cost advantages. (Halfduplex mobiles in TDMA systems transmit and receive in different timeslots and therefore do not require a duplexer). In the previous GSM,GPRS and EGPRS Phase 1, corresponding time slots on the uplink anddownlink were chosen in such a way that they were compatible withhalf-duplex operation. With statistical multiplexing, the system can bespecifically design for maximum flexibility of operation with halfduplex mobiles, when both the uplink and downlink time slots aredynamically assigned The new control and traffic channels are designedto support half-duplex mobiles in a manner that maximizes the pool oftraffic and control channel resources available for assignment to thesemobiles.

[0049] In what follows, a method for interleaving of half rate channelssuitable for half duplex operation and statistical multiplexing.According to the present invention, an alternative (0246/1357) burstinterleaving for half rate channels was found to offer the followingadvantages: larger resource pools for statistical multiplexing underhalf duplex constraints imposed by mobile station class; lower delay tothe start of a talkspurt; and better link level performance when thereis no frequency hopping or when frequency hopping is non-ideal.

[0050] The ability to multiplex and transmit voice and data and the playout delays for speech were found to be equivalent for both the known(0123/4567) interleaving method and the (0246/1357) interleaving methodof the present invention.

[0051] Application of Interleaving of Both Half Rate and Full RateChannels Suitable for Half Duplex Operation to GERAN (GSM EDGE (EnhancedGeneral Packet Radio Service) Radio Access Network)

[0052] GERAN document 2E99-584 in pertinent part reads:

[0053] The GERAN description describes the key new ideas needed tointroduce statistical multiplexing of all bearer classes on the GERANair interface for delivery over the packet-switched network. It focusesonly on the support of overall UMTS service requirements, and does notaddress network architecture issues or circuit-switched services.

[0054] The central new service requirement for GERAN (compared to EGPRSPhase 1) is the support of speech service using the packet-switchedbackbone network. The focus of the document is the definition of newtraffic and control channels to support statistical multiplexing ofspeech, real-time data, and non-real-time data, and the correspondingnew MAC procedures that are needed to guarantee QoS. List of Acronymsused herein AMR Adaptive Multi-Rate ARI Access Request Identifier BCCHBroadcast Control Channel BEP Bit Error Probability BFACCH Burst-basedFACCH CCCH Common Control Channel CID Carrier Identifier CTS CarrierTime Slot DBMCH Downlink Block Message Channel DFACCH Dim-and-BurstFACCH DMT Downlink (Burst) Message Type DPRCH Downlink PeriodicReservation Channel DTCH/FS Downlink Traffic Channel for Full RateSpeech DTCH/HS Downlink Traffic Channel for Half Rate Speech DTCH/FDDownlink Traffic Channel for Full Rate Data DTCH/HD Downlink TrafficChannel for Half Rate Data EDT End Downlink Traffic EEP Equal ErrorProtection EGPRS Enhanced General Packet Radio Service EUT End UplinkTraffic FACCH Fast Associated Control Channel FACKCH Fast AcknowledgmentChannel FASSCH Fast Assignment Channel FFS For Further Study FRFull-Rate FRACH Fast Random Access Channel GERAN GSM/EDGE Radio AccessNetwork HR Half-Rate IP Internet Protocol L1 Layer 1 (Physical Layer)MAC Medium Access Control MCS Modulation and Coding Scheme MRMeasurement Report MS Mobile Station MSACCH Modified Slow AssociatedControl Channel NRT Non-Real Time OFF Offset in Frames PBCCH PacketBroadcast Control Channel PCCCH Packet Common Control Channel PDCPPacket Data Convergence Protocol PH Phase QoS Quality of Service RABRadio Access Bearer RAN Radio Access Network RDC Reassign DownlinkControl RDT Reassign Downlink Traffic RLC Radio Link Control RR RadioResource Management RRBP Relative Reserved Burst Period RT Real Time RTPReal Time Protocol RUC Reassign Uplink Control RUT Reassign UplinkTraffic SACCH Slow Associated Control Channel SD Start Delay SDT StartDownlink Traffic SID Silence Descriptor SUT Start Uplink Traffic TBFTemporary Block Flow TBFI Temporary Block Flow Identifier TCP TransportControl Protocol TFI Temporary Flow Identifier TS Time Slot UDP UserDatagram Protocol UEP Unequal Error Protection UBMCH Uplink BlockMessage Channel UPRCH Uplink Periodic Reservation Channel UMT Uplink(Burst) Message Type UMTS Universal Mobile Telecommunications System USFUplink State Flag UTCH/FS Uplink Traffic Channel for Full Rate SpeechUTCH/HS Uplink Traffic Channel for Half Rate Speech UTCH/FD UplinkTraffic Channel for Full Rate Data UTCH/HD Uplink Traffic Channel forHalf Rate Data UTRAN UMTS Terrestrial Radio Access Network VAD VoiceActivity Detection

[0055] Service Requirements

[0056] Service requirements for GERAN are based on those of UMTS, withthe addition of an optimized speech service based on GSM/AMR. Theserequirements describe the radio bearer classes, the need for parallelbearer flows, handover, and alignment with UMTS core network. Specificerror, throughput, and delay requirements for each bearer class are FFS,but range of capabilities is clear from current UMTS requirements.

[0057] Support of Radio Bearer Classes in Alignment with UMTS

[0058] The UMTS radio bearer classes for conversational, streaming,interactive, and background services cover a range of real-time andnon-real-time data services with a wide range of error, throughput, anddelay requirements. The GERAN requirements for these services will bealigned with UMTS with adjustments as necessary to capture uniquecharacteristics of the GERAN.

[0059] Voice service requirements are based on those of GSM/AMR. A GERANradio bearer class will be specifically optimized for voice service.

[0060] Support for Parallel Bearer Flows with Different QoS

[0061] The GERAN shall support up to three parallel bi-directionalbearer flows with different QoS requirements. This capability willenable support of simultaneous voice and data service as well asmultimedia service.

[0062] Handover Requirement for RT Services

[0063] Voice and real-time data services have QoS characteristics notsupported by existing EGPRS reselection procedures. The GERAN shallinclude procedures to support maintenance of acceptable (TBD) QoS duringnetwork-assisted handover procedures for voice and real-time dataservices. The details of these handover procedures are outside the scopeof this document.

[0064] Alignment with UMTS Core Network

[0065] The GERAN shall conform to the core network interfacerequirements established for UMTS with only those changes necessary toadapt to unique characteristics of the GERAN. In particular, thisrequires that the GERAN provide the Iu-ps interface to the UMTS corenetwork.

[0066] Targeted Configuration

[0067] Blocking Limited Deployment

[0068] This concept proposal is optimized for blocking limiteddeployment, where the greatest capacity is achieved by utilizingavailable traffic-carrying channels to the fullest degree. In a blockinglimited deployment, traditional circuit channels for delivery of voiceand real-time data services are inefficient due to significant periodsof “dead time” during a typical flow. For voice service with a voiceactivity factor approximately 40%, there is considerable potential toincrease overall capacity with statistical multiplexing of trafficchannel resources.

[0069] Interference Limited Deployment

[0070] Since an interference-limited system must operate at somefraction of its channel capacity to achieve acceptable aggregateperformance, statistical multiplexing typically offers little or nocapacity advantage. However, interference-limited deployment (e.g. ⅓reuse) becomes blocking limited with techniques like beam forming andpower control. It is more appropriate to optimize the GERAN fordeployment configurations that take advantage of the application of thelatest interference management techniques, which make them more blockinglimited. This approach assures that the greatest capacity benefits areavailable in all configurations.

[0071] Less Aggressive Reuse (e.g. {fraction (4/12)}) Preferred whenSpectrum Available

[0072] Blocking limited deployment is and will be common for theforeseeable future. Blocking limited deployment is preferred in areasnot limited by availability of spectrum. It is also preferred in areaswhere uniform quality of service is a requirement, since coverage“holes” become more common when operating in interference limitedconditions.

[0073] All New Traffic and Control Channels

[0074] This invention introduces new traffic and control channels thatare completely compatible with beam forming and power controltechniques, enabling their use for all new traffic and control channels.This is achieved by designing all communication on these channels to bepoint-to-point. There are no multicast or broadcast control messages orcontrol fields in any downlink transmissions.

[0075] Multiplexing Principles

[0076] The benefits of statistical multiplexing are achieved through theapplication of the following principles.

[0077] Unidirectional Traffic and Control Channels

[0078] All new control and traffic channels are unidirectional, withindependent frequency and slot allocation in the uplink and downlinkdirections. Available resources can be dynamically allocated asnecessary to traffic and control channel functions. This allows formaximum flexibility in allocation of available resources. Breaking thehistorical association between uplink and downlink channels is necessaryfor statistical multiplexing of speech, in particular, since the uplinkand downlink resource demands occur independently. Breaking theassociation between uplink and downlink maximizes the resource poolavailable for assignment when new data or speech becomes available fortransmission.

[0079] A primary consideration for any new GERAN concepts must be theimpact on half-duplex mobiles, given their cost advantages. The newcontrol and traffic channels are specifically designed to supporthalf-duplex mobiles in a manner that maximizes the pool of traffic andcontrol channel resources available for assignment to these mobiles.

[0080] EGPRS Phase 1 and Phase 2 Traffic on Different Time Slots

[0081] Because of the need to allocate uplink and downlink channelsindependently, it is not possible to multiplex EGPRS Phase 1 and Phase 2(GERAN) traffic on the same time slot. This traffic must be segregatedonto separate time slots at any one time.

[0082] Multiplexing Different QoS Classes

[0083] This proposal supports the multiplexing of all QoS classes ontothe same channels. The same uplink an downlink resource pools are sharedamong all flows, regardless of their QoS class, maximizing theadvantages of statistical multiplexing.

[0084] Operation of TBF Establishment

[0085] The concept of a Temporary Block Flow (TBF) of GPRS/EGPRS isenhanced in the GERAN to have a unique profile with direction, QoS, andprotocol attributes.

[0086] Negotiation of TBF Profile

[0087] Before establishment of any TBF between a mobile and the network,it camps on the CCCH or PCCCH in the current cell, and is governed byprocedures currently defined in EGPRS. When the first TBF isestablished, its attributes are defined as follows:

[0088] The TBF is either unidirectional (uplink or downlink) orbi-directional. A voice TBF would typically be bi-directional. A dataTBF could be either unidirectional or bi-directional. Data trafficrequiring any significant exchange, such as upper layer acknowledgments,could be bi-directional, thus saving the overhead of repeated TBFestablishment for periodic traffic. The TBF is assigned QoS attributesconsistent with the desired service quality and bearer class. Given theassigned QoS attributes, the TBF may also be eligible fornetwork-directed handover procedures to minimize service disruptionwhile switching between two cells.

[0089] The TBF is assigned protocol attributes. For example, for voiceservice the TBF uses physical layer channel coding optimized for voice,and eliminates headers associated with other protocol layers. Dataservices will typically require physical layer channel coding optimizedfor data and the presence of the headers for all protocol layers tocontrol more complex protocol functions.

[0090] MAC Procedures for Established TBF

[0091] Once the first TBF is established, the mobile remains on the newRT traffic and control channels, regardless of the presence or absenceof data to send, until all TBFs for the mobile are released. Each TBFremains valid regardless of activity until it either times out or isexplicitly released by the network.

[0092] Channels for Fast Resource Assignment

[0093] When there is no data transfer in the downlink direction (nodownlink traffic channel is assigned to the TBF), the mobile mustmonitor a common downlink control channel for fast resource assignmentdirectives. These assignment directives assign traffic channel resourcesto the TBF as needed to support data transfer with the agreed-to QoSattributes.

[0094] When the TBF has an active downlink traffic channel assignment,it typically monitors the same physical channel for fast associatedcontrol channel messages with alternative assignment directives. As analternative for mobiles with adequate multi-slot capability, the mobilemay be required to monitor both the downlink traffic channel for userdata and a common downlink control channel for fast assignmentdirectives.

[0095] When a mobile has more than one TBF active in the downlinkdirection, it may be required to monitor either a common downlinkcontrol channel and/or one (or more) of the downlink traffic channelsfor fast assignment directives.

[0096] Traffic Channel Assignment

[0097] When the TBF requires a downlink traffic channel for datatransfer, the network sends a fast assignment directive to the mobile toallocate a downlink traffic channel for the data transfer.

[0098] When the TBF requires an uplink traffic channel for datatransfer, the mobile sends a fast access request on an uplink fastaccess control channel. The network responds with a fast assignmentdirective to allocate the necessary uplink resource.

[0099] In all cases, since QoS and protocol attributes have beennegotiated during establishment of the TBF, there is no ambiguity as tothe parameters of the resource request or assignment. These attributesdo not change from one resource request or assignment to the next duringa TBF.

[0100] Timing Alignment and Power Control

[0101] For as long as a mobile has at least one TBF established, itremains in timing alignment and under power control. This allows for allaccess bursts to be of normal length, since abbreviated bursts are notneeded to allow for misalignment. This also avoids the extra overhead ofperforming these functions at the beginning of each traffic channelassignment.

[0102] Protocol and Architecture

[0103] To support optimized speech, RT and NRT users over packet bearer,two different protocol stacks are proposed to meet the requirements ofoptimized speech and data bearers, as shown in FIG. 2.

[0104] The protocol stack used for a particular TBF is negotiated at theTBF setup along with the QoS attributes. For optimized speech bearer, adedicated unidirectional traffic channel is allocated to a speech TBFduring a talk spurt. Hence no RLC/MAC header is used. The IP/UDP/RTPheader information is exchanged at speech TBF setup and is, therefore,eliminated from the speech frame transmission over the RF interface. So,the entire shaded area of the protocol stack is dispensed with foroptimized speech users, but not for RT and NRT data users. For RT andNRT data users, the EGPRS Phase 2 protocol stack is kept. Possibleoptimization for RT data bearers is FFS.

[0105] RLC

[0106] The GERAN will reuse the EGPRS Phase 1 RLC with only thoseextensions needed to adapt RLC procedures to the new RT traffic andcontrol channels.

[0107] MAC

[0108] The RT MAC is new for the GERAN, based on the fast access andassignment procedures of this proposal.

[0109] Radio Interface Aspects

[0110] The GERAN Layer 1 is an enhanced version of the EGPRS Phase 1Layer 1. Enhancements are related to the introduction of new types oftraffic and control channels, as described below.

[0111] Traffic Channel Design

[0112] All traffic channels in GERAN are considered to be unidirectionalchannels. Chain interleaving is done on speech traffic channels andblock interleaving for data. Half-rate traffic channels use alternatebursts. This has a significant multiplexing advantage for half-duplexmobiles. In the case of NRT data, it permits ease of multiplexing withRT data and voice.

[0113] Speech, RT and NRT users may share a time slot by being assignedto two different half-rate channels on the same slot. A half-rate or afull-rate traffic channel is allocated to a specific speech or data userfor the duration of a talk spurt or “data spurt”. No headers or stealingbits are required for the receiver to distinguish between these trafficchannels. For data channels, stealing bits and header formats are usedas in EGPRS Phase I, but the USF is eliminated on the downlink.

[0114] All traffic channel assignments are through messaging on the newcontrol channels (including TCH associated control channels).

[0115] Speech Traffic Channel Design Principles

[0116] Speech traffic channels are based on supporting the GSM/AMR modeson full-rate and half-rate channels. The full-rate channel coding forthe GSM/AMR modes is the same as in current GSM/AMR. The channel codingfor half-rate AMR modes will be based on either 8PSK or QPSK modulation,depending on the results of separates studies.

[0117] Interleaving

[0118] Interleaving in all cases will be chain interleaving over 40msec, as in GSM/AMR. For a full-rate traffic channel the interleaving isover 8 radio bursts in 40 msec, with a chaining overlap of 4 radiobursts in 20 msec. For a half-rate traffic channel, the interleaving isover 4 radio bursts spaced over 40 msec, with a chaining overlap of 2radio bursts in 20 msec. This half-rate interleaving mode is sometimesdescribed as 0246/1357, to describe the use of alternate bursts for eachof two half-rate channels over the 8 bursts in a 40 msec interval. Thealternative of block interleaving of 2 speech frames over 4 consecutivebursts in 20 msec intervals alternating between two half-rate channelsis sometimes called 0123/4567 interleaving.

[0119] Compatibility with Half-Duplex Mobiles

[0120] Half-duplex mobiles typically have severe constraints on thecombination of uplink and downlink channels that they can support. Thisis an important consideration since statistical multiplexing works moreefficiently with a larger pool of resources available for allocation.Investigation has shown that the best statistical multiplexingefficiency is achieved for half-duplex mobiles by defining all half-ratetraffic and control channels to use no more than every other burst onany one time slot. This burst allocation for half-rate speech channelsis discussed below.

[0121] Headers

[0122] Since the entire channel (either full-rate or half-rate) isdedicated to a TBF for the length of a talk spurt, there is no need foradditional header beyond what is in existing GSM/AMR.

[0123] Half Speech Block

[0124] With chain interleaving, half of the information transmitted inthe first and last 20 msec intervals of a talk spurt is typicallyunusable. Since AMR has multiple compatible modes of operation withdifferent sizes of speech frames every 20 msec, it is possible to definenew channel coding for these currently unused bits to transmit specialspeech frames. For example, with the 7.4 kbps mode of operation, it ispossible to specify alternative channel coding on the first block ofunused bits to encode a single 4.75 kbps speech frame. The performanceof this half speech block is somewhat worse than the performance of theremaining speech frames, but the overall impact on the quality of atypical talk spurt is small.

[0125] Use of the half speech block reduces the delay to the beginningof a talk spurt by 20 msec. By starting a talk spurt with a half speechblock, the overall time on the traffic channel is also reduced by 20msec (corresponding to the first 20 msec interval typically needed tostart up a chain interleaving sequence. By using a half speech block forthe last speech frame of a talk spurt, which is relatively unimportantto the intelligibility of the talk spurt, the overall time on thetraffic channel is reduced by an additional 20 msec (for a total of 40msec). This is accomplished by eliminating the need to transmit the last20 msec portion of the last valid speech frame.

[0126] The half speech block could also be used in the middle of a talkspurt to free up room to transmit a frame of control information. Thisis called “dim-and-burst” signaling as opposed to “blank-and-burst”signaling, which replaces an entire speech frame with a frame of controlinformation. This “dim-and-burst” concept is introduced as a newassociated control channel below.

[0127] Initial Burst of a Talk Spurt

[0128] In GSM, interleaving must begin on a radio block boundary, whichoccurs every 20 msec. Since every talk spurt is specifically assigned toa traffic channel, it is not necessary to maintain this 20 msecgranularity. Allowing a talk spurt to begin on any burst improves theaverage delay to the beginning of a talk spurt by approximately 5 msecfor half-rate channels, since the assignment granularity is reduced from20 msec to 10 msec. The average improvement for full-rate channels isapproximately 7.5 msec, since the assignment granularity is reduced from20 msec to 5 msec.

[0129] AMR VAD and Hangover

[0130] The current AMR VAD and hangover interval are not designed toprovide optimal performance in a system with statistical multiplexing ofspeech. They are both candidates for further study to reduce the averagelength of talk spurts without significantly increasing the rate ofoccurrence of talk spurts (which would cause an increase in load on theRT control channels). For example, it should be possible to reduce thehangover interval from 7 frames to a lower number such as 2 or 3. It isnot yet known how this would impact control channel load or theoccurrence of speech clipping.

[0131] Data Traffic Channel Design Principles

[0132] The data traffic channels are designed for full compatibilitywith the speech traffic channels, while reusing the MCS1 through MCS9channel coding schemes defined for EGPRS.

[0133] Interleaving

[0134] For full-rate data channels, the interleaving is 0123/4567 blockinterleaving as defined in EGPRS. There is no need to deviate from EGPRSsince the TBF has exclusive use of the channel until it is explicitlyreassigned.

[0135] For half-rate data channels, the interleaving is 0246/1357 blockinterleaving, where each data block is interleaved over 4 consecutiveodd or even bursts (alternate bursts).

[0136] Compatibility with Half-Duplex Mobiles

[0137] As in the half rate speech section, half-rate data trafficchannels have the same advantages in statistical multiplexing efficiencyas half-rate speech traffic channels.

[0138] Headers

[0139] Since the entire channel (either full-rate or half-rate) isdedicated to a TBF for the length of a data spurt, there is no need foradditional header beyond what is in existing EGPRS. The USF is unusedand could be redefined for other purposes. The TFI is similarly unusedin this approach as defined, but has potential value for additional datamultiplexing options if replaced with the ARI and/or TBFI, as defined insection 0.

[0140] Initial Burst of a Talk Spurt

[0141] As mentioned above, data channels may begin a data spurt on anyassigned burst, offering the same improvement in delay to the beginningof the data spurt as for a talk spurt.

[0142] Traffic Channel Definition

[0143] The following traffic channels are defined.

[0144] Downlink Traffic Channel for Full Rate Speech (DTCH/FS). Thischannel comprises an entire time slot with eight burst chaininterleaving. This channel uses GMSK modulation and unequal errorprotection.

[0145] Downlink Traffic Channel for Half Rate Speech (DTCH/HS). Thischannel comprises one half of a time slot on alternate bursts with fourburst chain interleaving. Channel 1 on the time slot compriseseven-numbered bursts, channel 2 comprises odd-numbered bursts. Themodulation and coding schemes are to be specified.

[0146] Downlink Traffic Channel for Full Rate Data (DTCH/FD). Thischannel comprises an entire time slot with four burst blockinterleaving. EGPRS Phase I modulation and coding schemes (MCS1-MCS9)are used for the blocks. The USF is freed up.

[0147] Downlink Traffic Channel for Half Rate Data (DTCH/HD). Thischannel comprises one half of a time slot on alternate bursts with fourburst block-interleaving. Channel 1 on the time slot compriseseven-numbered bursts, channel 2 comprises odd-numbered bursts. EGPRSPhase I modulation and coding schemes (MCS1-MCS9) are used for theblocks (four alternate bursts). The USF is freed up.

[0148] Uplink Traffic Channel for Full Rate Speech (UTCH/FS). Thischannel comprises an entire time slot with eight burst chaininterleaving. This channel uses GMSK modulation and unequal errorprotection.

[0149] Uplink Traffic Channel for Half Rate Speech (UTCH/HS). Thischannel comprises one half of a time slot on alternate bursts with fourburst chain interleaving. Channel 1 on the time slot compriseseven-numbered bursts, channel 2 comprises odd-numbered bursts. Themodulation and coding schemes are to be specified.

[0150] Uplink Traffic Channel for Full Rate Data (UTCH/FD). This channelcomprises an entire time slot with four burst block interleaving. EGPRSPhase I modulation and coding schemes (MCS1-MCS9) are used for theblocks.

[0151] Uplink Traffic Channel for Half Rate Data (UTCH/HD). This channelcomprises one half of a time slot on alternate bursts with four burstblock interleaving. Channel 1 on the time slot comprises even-numberedbursts, channel 2 comprises odd-numbered bursts. EGPRS Phase Imodulation and coding schemes (MCS1-MCS9) are used for the blocks (fouralternate bursts).

[0152] Half-rate Traffic Channel Structure

[0153] Half-rate traffic channels comprise either even-numbered bursts(channel 0) or odd-numbered bursts (channel 1) of a time slot. This evenor odd burst allocation of a half-rate traffic channel is not changed ina multiframe. It is worth noting that for current GSM traffic channels,the burst allocation alternates every 13 frames within a multiframebetween odd bursts and even bursts. This change in burst allocation isnecessary for maximum compatibility with half-duplex mobiles.

[0154] For data traffic channels, there is no MSACCH, and all allocatedbursts in the time slot are available for traffic.

[0155] Multiplexing of Speech and Data Traffic

[0156] Two different half-rate traffic channels (speech or data) may beassigned to the two different phases, i.e. odd-numbered bursts oreven-numbered bursts, of a time slot. The speech traffic channels(half-rate or full-rate) are allocated to a speech user for the durationof a talk spurt. A simplified fixed allocation procedure allocates anentire data traffic channel (either full-rate or half-rate) continuouslyto a TBF for the duration of a data spurt.

[0157] There is no multiplexing with full-rate speech users during atalk spurt, or with full-rate data users during a data spurt. After afull-rate talk or data spurt ends, the corresponding time slot isavailable for allocation to a full-rate or half-rate voice or data TBF.

[0158] Real Time Control Channel Design

[0159] New RT control channels provide the fast resource allocationneeded to perform statistical multiplexing of voice and real-time dataservices. A burst-based contention access procedure allows a MS campedon the RT control channel to signal for uplink resource whenever anuplink traffic flow transitions from inactive to active (e.g. when thenext talk spurt starts for a speech user). The mobile's Access RequestIdentifier, ARI, is transmitted in the access burst, which allows thenetwork to immediately perform contention resolution. The network alsoincludes the ARI in single-burst fast assignment messages in thedownlink. Fast retry with 5 msec granularity increases the robustness ofthe single burst access and fast assignment scheme. Fast reassignmentand termination provides the network the ability to allocate andreallocate resources and satisfy the QoS of RT TBFs.

[0160] Control Channel Functions

[0161] The existing BCCH or PBCCH provides the broadcast informationneeded for the mobile to access the GERAN. The existing CCCH or PCCCHprovide the capability to negotiate the attributes of the initial TBFand to communicate the parameters needed for access to the RT controlchannels. Once in a voice, RT data or NRT data TBF, the followingfunctions are needed (unless an exception is listed).

[0162] Access Request

[0163] The mobile must have the ability to request uplink resources onbehalf of a TBF.

[0164] Traffic and Control Channel Assignment

[0165] The network must have the ability to make traffic and controlchannel assignments (for both uplink and downlink resources) to themobile.

[0166] End-of-TBF Control

[0167] The mobile must have the ability to request the network to end aparticular TBF. The network must have the ability to direct a mobile toimmediately terminate a TBF.

[0168] Acknowledgment of Network Directives

[0169] The mobile must have the ability to acknowledge traffic andcontrol channel assignments and end-of-TBF directives to trigger anynecessary retry procedures to assure rapid resource allocation.

[0170] Timing Advance and Power Control

[0171] The network must be able to signal to the mobile any necessaryadjustments in timing advance and power control.

[0172] Handover Signaling

[0173] If a mobile has an established TBF for voice or RT data, it iseligible for handover procedures. In this case, the mobile is requiredto provide periodic neighbor cell measurement reports to the network.The network will send the necessary handover directives to the mobile asappropriate to maintain the mobile under control of the RT controlchannels during and after handover to minimize service disruption.

[0174] Negotiation of Additional TBFs

[0175] It must be possible for either the mobile or network to beginnegotiation of additional TBFs while under control of the RT controlchannels, subject to the multi-slot capabilities of the mobile. Inparticular, it must be possible to establish a default data TBF forcontrol signaling while under control of the RT control channels.

[0176] AMR Signaling

[0177] During a voice TBF, it must be possible for the network to sendperiodic AMR mode commands to the mobile. During a voice TBF outside ofa downlink talk spurt, it must be possible for the network to sendperiodic SID information to the mobile.

[0178] During a voice TBF, it must be possible for the mobile to sendperiodic AMR mode requests to the network. During a voice TBF outside ofan uplink talk spurt, it must be possible for the mobile to sendperiodic SID information to the network.

[0179] RLC Signaling

[0180] RLC signaling may include, for example, ack/nack messages, andBEP measurements.

[0181] During a data TBF in the process of communicating in the downlinkdirection, it must be possible for the mobile to send periodic RLCcontrol messages to the network.

[0182] During a data TBF in the process of communicating in the uplinkdirection, it must be possible for the network to send periodic RLCcontrol messages to the mobile.

[0183] If a data traffic channel has already been allocated to a TBF ina direction requiring transmission of an RLC control message, existingRLC procedures already allow RLC control messages to be freelymultiplexed with RLC data frames.

[0184] Control Channel Design Principles

[0185] The key functions of the RT control channels that enablestatistical multiplexing are fast access, assignment, andacknowledgment. The following principles assure the rapid performance ofthese functions.

[0186] Burst-based Channels

[0187] All fast access, assignment, and acknowledgment channels usesingle burst messages. This assures high capacity, point-to-pointtransmissions for compatibility with beam steering and power controlprocedures, and fine temporal granularity, with a transmissionopportunity every 5 msec.

[0188] Access Request Identifier

[0189] Each mobile is assigned an ARI as a unique identifier duringaccess and assignment procedures on the RT control channels. Byincluding the ARI in the access burst, the network performs contentionresolution immediately rather than waiting for contention resolutionprocedures on a traffic channel, as in GPRS and EGPRS. The network mayrespond immediately with a single burst assignment message including theARI.

[0190] Half-Rate and Full-Rate Channels

[0191] The fast access, assignment, and acknowledgment channels aretypically allocated a full-rate channel with all the bursts in a givenslot. As an alternative, these channels may also be allocated ashalf-rate channels using either all odd or all even bursts in a slot.

[0192] Note in particular that a fast access channel is completelyallocated for contention access. The network does not broadcast USF tosignal contention opportunities. Since there is no need to monitor USF,this saves up to 40 msec in waiting to perform an access attempt incertain situations.

[0193] Fast Retry

[0194] Since all full-rate access, assignment, and acknowledgmentchannels have 5 msec granularity, this allows for rapid retry of theseprocedures up to once every 5 msec. Half-rate channels have a 10 msecgranularity. Even with a high error rate on these channels, access andassignment procedures can be performed quickly and efficiently. Notethat frequency hopping is desirable on these channels to reduce oreliminate burst-to-burst fading correlation.

[0195] Fast Control Channel Assignment

[0196] The fast access, assignment, and acknowledgment channels areallocated at the establishment of a TBF, and continue to be usedthroughout the TBF unless they are reassigned.

[0197] Associated Control Channel Definitions

[0198] Several new associated control channels are defined to supportthe necessary control channel functions while the mobile is active on atraffic channel in the direction that control signaling is required.

[0199] Fast Associated Control Channel (FACCH)

[0200] A FACCH is associated with each traffic channel defined in 0.Thus the FACCH associated with the DTCH/FS is referred to as FACCH/DFS,for FACCH on a downlink full-rate speech channel. Other FACCH channelsare named consistently. Standard FACCH coding as in GSM AMR bearer isused.

[0201] Dim-and-burst FACCH (DFACCH)

[0202] A DFACCH is associated with each traffic channel defined in 0.Thus the DFACCH associated with the UTCH/FS is referred to asDFACCH/UFS. Other DFACCH channels are named consistently.

[0203] DFACCH coding is for further study beyond the present invention.

[0204] Burst-based FACCH (BFACCH)

[0205] A BFACCH is associated with each traffic channel defined in 0.Thus the BFACCH associated with the DTCH/FS is referred to asBFACCH/DFS. Other BFACCH channels are named consistently.

[0206] Burst based control messages are transmitted over BFACCHreplacing single burst speech or data for fast access, assignment andacknowledgment while on a traffic channel. BFACCH is distinguished fromspeech or data traffic using a new training sequence or stealing bits.BFACCH channel coding is for further study.

[0207] Modified Slow Associated Control Channel (MSACCH)

[0208] A MSACCH is associated with each traffic channel defined in 0.Thus the MSACCH associated with the DTCH/FS is referred to asMSACCH/DFS. Other MSACCH channels are named consistently.

[0209] A MSACCH is a set of reserved bursts on a periodical basis andhas the same structure as SACCH defined for GSM speech traffic channels.

[0210] Block based signaling messages, e.g. Neighbor Measurement Report,are transmitted over MSACCH.

[0211] Common Uplink Control Channel Definition

[0212] Fast Random Access Channel (FRACH)

[0213] A FRACH is designed to transmit single burst fast contentionaccess messages. The traffic on the FRACH is isolated from the RACH andPRACH. Since the mobiles accessing on the FRACH are assumed to betime-aligned, the guard period on the FRACH burst is shorter and themessage size can be larger. The maximum message length on the FRACH isTBD.

[0214] A FRACH comprises either a full time slot on all bursts(full-rate), or a half time slot on alternate bursts (half-rate).

[0215] Fast Acknowledgment Channel (FACKCH)

[0216] A FACKCH is designed to transmit single burst messages toacknowledge assignments and termination directives from the network.FACKCH transmissions occur in reserved bursts.

[0217] Single burst acknowledgment message is transmitted on FACKCH on apolled basis using a RRBP scheme. This permits multiple burst-basedassignment/acknowledgment sequences to be completed within a 20-msecblock period and improves the speed and reliability of real-timestatistical multiplexing.

[0218] A FACKCH comprises either a full time slot on all bursts(full-rate), or a half time slot on alternate bursts (half-rate).

[0219] Uplink Periodic Reservation Channel (UPRCH)

[0220] An UPRCH is used to transmit signaling messages that need to beupdated on a periodic basis, e.g. SID_Update and Neighbor MeasurementReport. It is possible that a traffic channel is relinquished (e.g. whena talk spurt ends) before a signaling message (e.g. spans 480 ms) istransmitted completely on the MSACCH. An UPRCH is designed for MSACCHsignaling continuity when an uplink traffic channel is released.

[0221] An UPRCH is released at the assignment of an uplink trafficchannel, and is reassigned each time at the release of an uplink trafficchannel.

[0222] A UPRCH comprises either a full time slot on all bursts(full-rate), or a half time slot on alternate bursts (half-rate). Thenetwork reserves one of every 26 bursts on a full-rate UPRCH for eachvoice TBF not in an uplink talk spurt. 26 voice TBFs can simultaneouslyshare a full-rate UPRCH.

[0223] Uplink Block Message Channel (UBMCH)

[0224] An UBMCH is designed for block (4 bursts) messages, e.g. RLCsignaling, using polled reservation bursts in a RRBP-like scheme.

[0225] Common Downlink Control Channel Definition

[0226] Fast Assignment Channel (FASSCH)

[0227] A FASSCH is designed to transmit single burst assignment andtermination messages when there is no downlink traffic allocated to theMS. Different messages are used to assign downlink traffic channels,downlink control channels, uplink traffic channels, and uplink controlchannels.

[0228] A FASSCH comprises either a full time slot on all bursts(full-rate), or a half time slot on alternate bursts (half-rate).

[0229] Downlink Periodic Reservation Channel (DPRCH)

[0230] A DPRCH is used to transmit signaling messages that need to beupdated on a periodic basis, e.g. SID_Update, timing advance, and powercontrol. It is possible that a traffic channel is relinquished (e.g.when a talk spurt ends) before a signaling message (e.g. spans 480 ms)is transmitted completely on the MSACCH. A DPRCH is designed for MSACCHsignaling continuity when a downlink traffic channel is released.

[0231] A DPRCH is released when the downlink traffic channel isassigned, and reassigned each time at the release of the downlinktraffic channel.

[0232] A DPRCH comprises either a full time slot on all bursts(full-rate), or a half time slot on alternate bursts (half-rate). Thenetwork reserves one of every 26 bursts on a full-rate DPRCH for eachvoice TBF not in a downlink talk spurt. 26 voice TBFs can simultaneouslyshare a full-rate DPRCH.

[0233] Downlink Block Message Channel (DBMCH)

[0234] A DBMCH is designed for block (4 bursts) messages, e.g. RLCsignaling, handover directives, etc.

[0235] Multiplexing of Common Control Channel

[0236] The FRACH, FACKCH, UPRCH, FASSCH, and DPRCH may be eitherfull-rate or half-rate control channels. A full-rate control channeluses all bursts in each multiframe. A half-rate control channels useseither every odd or every even burst in each multiframe.

[0237] These channels are not multiplexed on the same full-rate orhalf-rate channel.

[0238] Two different half-rate control or traffic channels may beassigned to the two different phases (all odd or all even) of a slot.Note that the burst allocation for half-rate control channels iscompatible with and identical to the burst allocation for half-ratetraffic channels.

[0239] The multiplexing of DBMCH and UBMCH with other common controlchannel is FFS.

[0240] Overview of Real Time TBF Operation

[0241] The definition of TBF (GPRS Phase 1) is enhanced to support RTservices. Each RT TBF may be bi-directional (e.g. speech) orunidirectional (e.g. best effort data). The initial establishment of aRT TBF is carried on a PCCCH or CCCH. Each RT TBF has an associated TBFprofile. The negotiation of a RT TBF profile during TBF setup includesthe QoS requirements and the protocol stack supported by the RAB.

[0242] Additional information that is exchanged during initial TBF setupincludes the following:

[0243] A temporary MS Access Request Identifier, ARI, is allocated bythe network and is sent to the MS.

[0244] Carrier information (including frequency-hopping sequence) iscommunicated to the MS, either by broadcast message over PBCCH/BCCH orexplicit signaling. The details are FFS.

[0245] TBF identifier (TBFI) is assigned to the MS per requested TBF.

[0246] TBF Inactivity Timer is negotiated for RT and NRT data TBFs. Itis optional for RT speech TBF (FFS).

[0247] Once a RT TBF is established, the MS is assigned a set of RTcontrol channels, namely FRACH, FACKCH, UBMCH and UPRCH for uplinksignaling, and FASSCH, DBMCH and DPRCH for downlink signaling andcontrol. An UPRCH (or a DPRCH) may be reassigned each time an UTCH (or aDTCH) is released. The rest of the control channels, i.e. FRACH, FACKCHand UBMCH for uplink, and FASSCH and DBMCH for downlink, do not need tobe reassigned for the duration of the TBF.

[0248] The uplink and/or downlink traffic associated with the RT TBF isactivated independently using fast access and fast assignmentprocedures. Additional RT and NRT TBF(s) can be negotiated andestablished on the RT control channel(s).

[0249] An established bi-directional TBF has the following 4 states: TBFInactive, DL Active, UL Active, and DL and UL Active. The statetransition diagram for a single bi-directional RT TBF is shown in FIG.6. The state transitions for a unidirectional RT TBF and NRT TBF (asdefined in EGPRS Phase 1) are a subset of the states and allowabletransitions associated with bi-directional RT TBF.

[0250] RT TBF State Definition

[0251] An established bi-directional RT TBF has four states, as shown inFIG. 6. Channel allocation is also shown in FIG. 5 (Table 1).

[0252] RT TBF State: DL Inactive

[0253] In this state, there is no uplink or downlink traffic channelassigned to the MS for the TBF. The MS and the network may independentlyinitiate uplink and downlink traffic, set up a new TBF, end a currentTBF, or end all TBFs associated with the MS. The network may alsoreassign common control channels to the MS.

[0254] A timer may be associated with this state per RT TBF, whichallows the MS to be in TBF established state for a configurable timeafter the downlink and uplink traffic end. This avoids re-negotiation ofthe RT TBF profile, should downlink or uplink traffic flow resume withina short period of time.

[0255] RT TBF State: DL Active

[0256] In this state, the MS is assigned a downlink traffic channelassociated with the RT TBF. Downlink single burst messages aretransmitted using BFACCH. Other downlink signaling and control messagesare transmitted using FACCH and/or MSACCH.

[0257] Uplink signaling and control messages are carried on uplinkcommon channels assigned to the MS, which are shared among parallel TBFsthe MS may have established.

[0258] New TBFs may be initiated on the RT control channels.

[0259] RT TBF State: UL Active

[0260] In this state, the MS is assigned an uplink traffic channelassociated with the RT TBF.

[0261] Uplink single burst messages are transmitted using BFACCH. Otheruplink signaling and control messages are transmitted using FACCH and/orMSACCH.

[0262] Downlink signaling and control messages are carried on downlinkcommon control channels assigned to the MS, which are shared amongparallel TBFs the MS may have established.

[0263] New TBFs may be initiated on the RT control channels.

[0264] RT TBF State: DL and UL Active

[0265] In this state, the MS is assigned an uplink traffic channel and adownlink traffic channel associated with the RT TBF.

[0266] Both downlink and uplink single burst messages are transmittedusing BFACCH. Other signaling and control messages are transmitted usingFACCH and/or MSACCH.

[0267] New TBFs may be initiated on the RT control channels.

[0268] Procedures Associated with Single RT TBF State Transition

[0269] A set of procedures is defined to perform the state transitionsassociated with an RT TBF. FIG. 6 (table 2) shows the proceduresassociated with each single RT TBF state transition and the applicablestates involved. The definitions and message flows for the proceduresare further described below.

[0270] Control Messages

[0271] Uplink Signaling and Control Messages

[0272]FIG. 7 (table 3) provides a summary of the uplink signaling andcontrol messages and the control channels used.

[0273] Access Request

[0274] This single burst message is sent over BFACCH if an UTCH isallocated; otherwise it is sent over FRACH. Its usage and contents arefurther described in Section 0.

[0275] Acknowledge to Assignment

[0276] This set of single burst messages is sent over BFACCH if an UTCHis allocated; otherwise they are sent over FACKCH. Their usage andcontents are further described later in the section devoted to thatissue.

[0277] AMR Mode Request

[0278] AMR Mode Request (2 bits) is sent in-band if an UTCH isallocated. Otherwise, it is sent over UPRCH, multiplexed with otherperiodic signaling messages, e.g. SID Update and Neighbor MeasurementReport. The details of the multiplexing of these messages are FFS.

[0279] SID Update

[0280] Sid Update is sent over UPRCH, multiplexed with AMR Mode Requestand Neighbor Measure Report.

[0281] Neighbor Measurement Report

[0282] It is sent over MSACCH if a UTCH is allocated; otherwise, it issent over UPRCH, multiplexed with other periodic signaling messages,e.g. SID Update and AMR Mode Request.

[0283] RLC Signaling

[0284] RLC signaling is sent over a UTCH or UBMCH, according to EGPRSPhase 1 RLC procedures.

[0285] End TBF Request

[0286] This single burst message is sent on BFACCH or FRACH. Its usageand contents are further described below.

[0287] Downlink Signaling and Control Messages

[0288]FIG. 8 (table 4) provides a summary of the downlink signaling andcontrol messages, and the RT control channels used.

[0289] Assignment

[0290] All Assignment messages are burst based. They are sent overBFACCH if a DTCH is allocated; otherwise they are sent over FASSCH.Their usage and contents are further described below.

[0291] AMR Mode Command

[0292] AMR Mode Command (2 bits) is sent inband if a DTCH is allocated.Otherwise, it is sent over DPRCH, multiplexed with other periodicsignaling messages, e.g. SID Update and Timing Advance. The details ofthe multiplexing of these messages are FFS.

[0293] SID Update

[0294] SID_Update is sent over DPRCH, multiplexed with AMR Mode Commandand Timing Advance.

[0295] Handover Directives

[0296] Handover Directives are sent over FACCH if a DTCH is allocated;otherwise they are sent over DBMCH.

[0297] RLC Signaling

[0298] RLC signaling is sent over a DTCH or DBMCH, according to EGPRSPhase 1 RLC procedures.

[0299] Timing Advance

[0300] Timing Advance is sent over MSACCH if a DTCH is allocated to theMS; otherwise it is sent over DPRCH.

[0301] Power Control

[0302] Power Control is sent over MSACCH if a DTCH is allocated to theMS; otherwise it is sent over DPRCH.

[0303] End TBF Command

[0304] This single burst message is sent on BFACCH or FASSCH by thenetwork to terminate a single TBF or all TBFs established by the MS. Itscontents are further described below.

[0305] Downlink Burst Message Contents

[0306]FIG. 9 (table 5) provides a summary of downlink burst messages andtheir content.

[0307] Assign UTCH

[0308] This message is used to allocate an UTCH per specified TBF(identified by TBFI). The ARI field is included for fast contentionresolution.

[0309] Deferred Assign UTCH

[0310] This message is used to delay assignment of UTCH for thespecified TBF (identified by TBFI). The delay field indicates the periodfor which the mobile must wait for an assignment of uplink resourcebefore it may try again.

[0311] Assign DTCH

[0312] This message is used to allocate a DTCH per specified TBF(identified by TBFI). RRBP field is used to indicate the reserved burstfor sending the acknowledgment.

[0313] Assign UPRCH

[0314] This message is used to allocate an UPRCH to an MS for uplinkperiodic signaling when there is no UTCH assigned to the MS. The UPRCHis reassigned when an UTCH is released and the periodic uplink signalingon the MSACCH needs to continue on the UPRCH.

[0315] Assign DPRCH

[0316] This message is used to allocate a DPRCH to an MS for downlinkperiodic signaling when there is no DTCH assigned to the MS. The DPRCHis reassigned when a DTCH is released and the periodic downlinksignaling on the MSACCH needs to continue on the DPRCH.

[0317] Assign FRACH

[0318] This message is used to allocate an uplink FRACH to an MS forfast contention access. A FRACH is assigned to an MS at the initial TBFsetup and is usually not changed for the duration of the establishedTBF.

[0319] Assign FACKCH

[0320] This message is used to allocate an uplink FACKCH to an MS forsending acknowledgment on reserved bursts when polled. A FACKCH isassigned to an MS at the initial TBF setup and is usually not changedfor the duration of the established TBF.

[0321] Assign FASSCH

[0322] This message is used to allocate a downlink FASSCH to an MS formonitoring assignment messages. A FASSCH is assigned to an MS at theinitial TBF setup and is usually not changed for the duration of theestablished TBF.

[0323] End TBF Command

[0324] This message is used by the network to terminate one TBF(identified by TBFI) or all TBFs (TBFI=0) established by a MS.

[0325] Uplink Burst Message Contents

[0326]FIG. 10 (table 6) provides a summary of uplink burst messages andtheir contents.

[0327] Access Request

[0328] This message is used by an MS to request for UTCH per specifiedTBF (identified by TBFI).

[0329] Acknowledge UTCH/DTCH/UPRCH/DPRCH/FRACH/FACKCH/FASSCH

[0330] The MS uses this set of messages to acknowledge traffic andcontrol channel assignments.

[0331] Acknowledge End TBF

[0332] The MS uses this message to acknowledge an End TBF Command.

[0333] End TBF Request

[0334] The MS uses this message to request for termination of a TBF orall TBFs (TBFI=0) established by the MS. Information Element DefinitionLength IE Name (bits) Description ARI Access Request Identifier 9Uniquely identifiers each MS on RT control channel DMT Downlink MessageType 4 Identifies downlink burst message type UMT Uplink Message Type 4Identifies uplink burst message type TBFI TBF Identifier 2 Identifies 1of 3 possible TBFs in use by a MS; 0 identifies all TBFs for a MS RRBPRelative Reserved Burst 2 Offset to reserved uplink Period burst foracknowledgment of assignment CID Carrier Identifier 4 Identifies up to16 carriers in current cell; Carrier descriptions provided on PBCCH orPCCCH CTS Carrier Time Slot 3 Time slot number on assigned carrier. PHPhase 2 Indicates full-rate or half- rate, and odd bursts or even burstsSD Start Delay 1 Indicates whether to start on 1^(st) or 2^(nd) eligibleburst of a radio block OFF Offset 5 Frame number in each 26- multiframefor periodic allocation delay Delay 6 The number of 40 msec intervals amobile must wait before it may again try to request an uplink trafficchannel reason Reason Code 2 Further status for End TBF command/request

[0335] The methods described above has been applied to a system foraccess and assignment to real-time and non-real-time services in GERANas follows. The following four subsections describe the four keyprocedures needed to perform real-time scheduling of uplink and downlinktraffic channel resources (UTCH and DTCH, respectively) in a system thatstatistically multiplexes voice, real-time data, and non-real-time data.Each flow of data is called a TBF (temporary block flow). Accessrequests occur on a fast random access channel (FRACH). Traffic channelassignments occur on either a common fast assignment channel (FASSCH) ifthe mobile is not on a downlink traffic channel, or on a burst-basedfast associated control channel (BFACCH) that steals a single burst fromongoing downlink traffic. One of the four bursts of a traffic channelblock is blanked and replaced with a burst-based control message.Acknowledgments to assignments occur on either a common fastacknowledgment channel (FACKCH) if the mobile is not on an uplinktraffic channel, or on a BFACCH. At the end of an uplink (downlink) talkspurt or data spurt, the network reallocates an uplink (downlink)periodic reservation channel [UPRCH (DPRCH)] to allow continuity of slowassociated control signaling between the mobile and the network.

[0336] Start Uplink Traffic (SUT)

[0337] As shown in FIG. 11, a mobile station (MS) uses the SUT procedureto start an uplink traffic flow associated with a TBF. The uplinktraffic flow is directed to a base station which is part of a networkusing GERAN methods.

[0338] End Uplink Traffic (EUT)

[0339] As shown in FIG. 12, the network and the MS use the EUT procedureto terminate an uplink traffic flow associated with a TBF.

[0340] Start Downlink Traffic (SDT)

[0341] As shown in FIG. 13, the network uses the SDT procedure to starta downlink traffic flow associated with a TBF.

[0342] End Downlink Traffic (EDT)

[0343] As shown in FIG. 14, the network uses the EDT procedure toterminate a downlink traffic flow associated with a TBF.

[0344] Reassign Uplink Traffic (RUT)

[0345] As shown in FIG. 15, the network uses the RUT procedure to assigna new uplink traffic channel to the MS associated with a TBF.

[0346] Reassign Downlink Traffic (RDT)

[0347] As shown in FIG. 16, the network uses the RDT procedure to assigna new downlink traffic channel to the MS associated with a TBF.

[0348] Reassign Uplink Control (RUC)

[0349] As shown in FIG. 17, the network uses the RUC procedure to assigna new uplink control channel to the MS.

[0350] Reassign Downlink Control (RDC)

[0351] As shown in FIG. 18, the network uses the RDC procedure to assigna new downlink control channel to the MS.

[0352] End TBF (ET)

[0353] As shown in FIG. 19, the ET procedure is used to terminate a TBFor all TBFs. The End TBF procedure may also be used in Error cases forall other scenarios. Whenever error occurs during Assignment, either theMS or the network may abort the on-going procedure using End TBFmessages.

[0354] Performance results

[0355] For Interleaving for Half Rate Channels in EGPRS Phase II

[0356] Half-rate traffic channels comprise either even-numbered bursts(channel 0) or odd-numbered bursts (channel 1). The known GSM half ratechannels are shown in FIG. 20. It is worth noting that the burstsallocation changes every 13 frames within a multiframe in GSM definedhalf-rate speech channels. Hence channel 1 is assigned bursts 2j, j=0,1, 2, 3, 4, 5, 6 in multiframe 0. In multiframe 1, channel 1 consists ofbursts 2j+1, j=6, 7, 8, 9, 10, 11. Therefore, a mobile assigned tochannel one has to receive on even bursts in one multi-frame andodd-bursts in the next multiframe. This switching between even and oddbursts is not well suited for dynamic assignment of uplink and downlinkchannels.

[0357]FIG. 21 shows a half-rate traffic channel structure according tothe present invention. Here even-numbered bursts or odd-numbered burstsallocation is not changed for the duration of the assignment. Note that,unlike in the known GSM half rate traffic channel structure, here amobile station on channel 1 always reads only the even bursts, fortraffic as well as for MSACCH, i.e., bursts 2j, j=0, 1, 2, . . . . TheMSACCH is also on even bursts 2j, j=6, 19, 32, . . . . This small changefrom the GSM half rate channel is critical for flexibility with halfduplex operation on dynamically assigned time slots.

[0358] Also, half-rate control channels are defined with the samestructure, that is, on all even or all odd numbered frames.

[0359] Half Duplex Operation

[0360] Higher efficiency can be achieved through statisticalmultiplexing when a large pool of resources is available for assignment.However, half duplex (i.e., Type I) mobile stations constrain thechannels that can be assigned in the uplink and downlink directions.This impacts the resources available for assignment of traffic andcontrol channels. The resource constraints imposed by a half duplexmobile station may differ depending on its functions during differentperiods of activity. The periods of activity to be considered are asfollows:

[0361] No traffic in either direction—assignment of uplink controlchannels is constrained by downlink control channels and vice versa

[0362] Traffic in the downlink only—assignment of downlink trafficchannel is constrained by uplink control channels and vice versa

[0363] Traffic in the uplink only—assignment of uplink traffic channelis constrained by downlink control channels and vice versa

[0364] Traffic in both directions—assignment of uplink traffic channelis constrained by downlink traffic channel and vice versa

[0365] As an illustrative example, consider the case where an uplinktalkspurt is in progress, and a downlink talkspurt is just starting.FIG. 22 shows the half rate channels to which a downlink talkspurt for aClass 1 mobile station can be allocated when 0246/1357 interleaving isassumed. If the mobile is assumed to be active during odd (1357) burstson uplink time slot 5 (which overlaps with downlink time slot 0), thenon the downlink it can be allocated even bursts on time slots 3 through7 and odd bursts on time slots 0 through 4. Therefore, it can beassigned to 10 of 16 possible half rate channels on the downlink. Ifconsecutive burst (0123/4567) interleaving is assumed, the mobilestation can only be assigned to 7 out of 16 possible half rate channelson the downlink (see FIG. 23). FIGS. 24 and 25 illustrate thecorresponding resource availability for a Class 8 mobile station. Inboth cases, for these classes of mobile stations that the resource poolavailable for assignment of traffic channels is 43% larger with0246/1357 interleaving than with 0123/4567 interleaving can be observed.

[0366]FIG. 22 shows a resource pool to which a downlink talkspurt for aClass 1 (half duplex, single slot capable, T_(ta)=3, T_(rb)=2,T_(tb)=T_(ra)=0) MS may be allocated; 4 burst interleaving is assumedwhere interleaving is carried out over alternate (odd/even) bursts.

[0367]FIG. 23 shows a resource pool to which a downlink talkspurt for aClass 1 (half duplex, single slot capable, T_(ta)=3, T_(rb)=2,T_(tb)=T_(ra)=0) MS may be allocated; 4 burst interleaving is assumedwhere interleaving is carried out over consecutive bursts.

[0368]FIG. 24 shows a resource pool to which downlink transmissions fora Class 8 (half duplex, downlink 4-slot capable, T_(ta)=4, T_(rb)=1,T_(tb)=T_(ra)=0) MS may be allocated; 4 burst interleaving is assumedwhere interleaving is carried out over alternate bursts.

[0369]FIG. 25 shows a resource pool to which downlink transmissions fora Class 8 (half duplex, downlink 4-slot capable, T_(ta)=4, T_(rb)=1,T_(tb)=T_(ra)=0) MS may be allocated; 4 burst interleaving is assumedwhere interleaving is carried out over consecutive bursts.

[0370]FIG. 26 shows bursts on which a downlink talkspurt may start for aClass 1 (half duplex, single slot capable, T_(ta)=3, T_(rb)=2,T_(tb)=T_(ra)=0) MS; alternate burst interleaving is assumed.

[0371]FIG. 27 shows bursts on which a downlink talkspurt may start for aClass 1 (half duplex, single slot capable, T_(ta)=3, T_(rb)=2,T_(tb)=T_(ra)=0) MS; consecutive burst interleaving is assumed.

[0372] Delay in Starting Talkspurt (Half Rate)

[0373] Again, consider the case of the mobile that is active during odd(1357) bursts on uplink time slot 5 (which overlaps with downlink timeslot 0). Then on the downlink it can be allocated even bursts on timeslots 3 through 7 and odd bursts on time slots 0 through 4. FIG. 26shows the bursts during which a downlink talkspurt may start for a Class1 mobile station when 0246/1357 interleaving is used. FIG. 26 also showsthe bursts during which a downlink talkspurt may start when 0123/4567interleaving is used.

[0374] Given an available half rate channel on the downlink, that can beassigned to the Class 1 mobile (under the duplex constraints), thefollowing can be observed:

[0375] Granularity in start time for transmission (see FIGS. 26 and 27)is 40 ms for 0123/4567 interleaving and 10 ms for 0246/1357 interleavingif it is assumed that the interleaving sequence can start on any burst;and

[0376] Average delay to start (see FIGS. 26 and 27) is 20 ms for0123/4567 interleaving and 5 ms for 0246/1357 interleaving.

[0377] Performance of Interleaving for Half Rate Channels

[0378] The performance of the two different interleaving schemes forhalf rate channels discussed above is summarized in the table of FIG.28. With ideal frequency hopping, the performance of the 0246/1357interleaver is slightly worse than the 0123/4567 interleaver. However,with no frequency hopping, the 0246/1357 interleaver exhibits a gain of1.0 dB over the 0123/4567 interleaver for a slow fading typical urbanchannel. The 0246/1357 interleaver exhibits a modest gain of 0.4 to 0.8dB even in a fast fading channel.

[0379]FIG. 29 is a table showing performance of the two interleavingmethods with QPSK modulation.

[0380] For Interleaving for Full Rate Channels in EGPRS Phase II

[0381]FIG. 30 shows the resource pool to which a Full Rate downlinktalkspurt for a Class 1 (half duplex, single slot capable, T_(ta)=3,T_(rb)=2, T_(tb)=T_(ra)=0) MS may be allocated. A Full Rate channeloccupies an entire slot (both even and odd bursts).

[0382]FIG. 31 shows the resource pool to which a Full Rate downlinktalkspurt for a Class 1 (half duplex, single slot capable, T_(ta)=3,T_(rb)=2, T_(tb)=T_(ra)=0) MS may be allocated; 4 burst interleaving isassumed where interleaving is carried out over alternate (odd/even)bursts. A Full Rate channel in FIG. 31 is defined as the aggregation oftwo half rate channels on consecutive bursts.

[0383] In presently known GSM, Full Rate channels occupy an entiretimeslot as shown in FIG. 30. For a Class 1 mobile with a talkspurtactive on uplink time slot 5, a starting downlink talkspurt can beassigned only on downlink timeslot 3 or 4, which is 2 of 8 (25%)downlink timeslots on each carrier. This does not efficiently use thesystem resource pool and bandwidth.

[0384] According to one embodiment of the present invention, a newmethod and system to improve the number of available resources for FullRate channels is set forth. The new method and system for Full Ratechannels use an interleaving scheme described previously for half ratechannels. In order to maximize the number of resources on which thestarting downlink talkspurt can be assigned, the Full Rate channel forEGPRS Phase 2 is re-defined. The Full Rate channel in EGPRS Phase 2 isre-defined as two half rate channels on consecutive timeslots. FIG. 31shows an example in which the Full Rate uplink talkspurt is acitve onthe odd bursts of uplink time slots 5 and 6. The re-definition nowallows the downlink talkspurt to be assigned to the following downlinktimeslot pairs: the even bursts of timeslot pairs (4,5), (5,6), (6,7),even bursts of time slot 7 and odd bursts of time slot 0, and the oddbursts of time slots (0,1), (1,2), (2,3), (3,4).

[0385] Thus a total of eight of the sixteen (50%) possible timeslotpairs can be assigned while still satisfying the half duplex constraintof the Class 1 mobile. The Full Rate Channel method and system accordingto the present invention offer significant advantages in statisticalmultiplexing of Full Rate channels over the statistical multiplexing ofthe previously known interleaving scheme for Full Rate channels.

[0386] Delay in Starting Talkspurt (Full Rate)

[0387] For the new, re-defined full rate channel, given an availablefull rate channel on the downlink, that can be assigned to the Class 1mobile (under the duplex constraints), the following can be observed:

[0388] Granularity in start time for transmission: (see FIGS. 30 and 31)10 ms for 0246/1357 interleaving if it is assumed that the interleavingsequence can start on any burst; and

[0389] Average delay to start:(see FIGS. 30 and 31) 5 ms for 0246/1357interleaving.

[0390] In summary, the alternate (0246/1357) burst interleaving for halfrate channels offers the following advantages: larger resource pools forstatistical multiplexing under half duplex constraints imposed by mobilestation class; lower delay to the start of a talkspurt; and better linklevel performance when there is no frequency hopping or when frequencyhopping is non-ideal.

[0391] The ability to multiplex voice and data and the play out delaysfor speech are equivalent for both interleaving approaches. Therefore,it is concluded that 0246/1357 offers significant advantages without anypenalties, and 0246/1357 burst interleaving is the preferred approachfor EGPRS Phase II half rate channels.

[0392] Additionally, because of the re-definition of a full rate channelas two consecutive half rate channels, it is concluded that the fullrate channel according to the present invention likewise offers theadvantage of larger resource pools for statistical multiplexing underhalf duplex constraints.

[0393] Thus, it will now be understood that there has been disclosed anew, advantageous system and method for multiplexing and interleavingfull rate channels which use two consecutive half rate channels. Whilethe invention has been particularly illustrated and described withreference to preferred embodiments thereof, it will be understood bythose skilled in the art that changes in form, details and applicationsmay be made therein. It is accordingly intended that the appended claimsshall cover all such changes in form, details and applications which donot depart from the true spirit and scope of the invention.

1. A system for communicating using wireless time division multiplexedcommunications in which time is divided into a plurality of frames andeach frame is divided into N data bursts, said system comprising: meansfor defining a half rate channel as a series of bursts that occurperiodically every N bursts once per frame; means for defining a fullrate channel as two consecutive half rate channels; and means fortransmitting said full rate channel from a first station to a secondstation.
 2. The system of claim 1 , wherein 0246/1357 interleaving isused for said full rate channel.
 3. The system of claim 1 , wherein0246/1357 interleaving is used with non-ideal frequency hoppingtransmitting of said full rate channel because of the improved linkperformance provided thereby.
 4. The system of claim 1 , wherein0246/1357 interleaving is used because of a lower delay to the start ofa talkspurt of said half rate channels and hence said full rate channelthan 0123/4567 interleaving.
 5. The system of claim 1 , wherein0246/1357 interleaving is used because of larger resource pools forstatistical multiplexing under half duplex constraints imposed by mobilestations provided for said full rate channel relative to 0123/4567interleaving.
 6. A system for communicating using wireless time divisionmultiplexed communications in which time is divided into a plurality offrames and each frame is divided into N data bursts, said systemcomprising: a first multiplexer defining a half rate channel as a seriesof bursts that occur periodically every N bursts once per frame; asecond multiplexer defining a full rate channel as two consecutive halfrate channels; and a transmitter transmitting said full rate channelfrom a first station to a second station.
 7. The system of claim 6 ,wherein 0246/1357 interleaving is used for said full rate channel. 8.The system of claim 6 , wherein 0246/1357 interleaving is used withnon-ideal frequency hopping transmitting of said full rate channelbecause of the improved link performance provided thereby.
 9. The systemof claim 6 , wherein 0246/1357 interleaving is used because of a lowerdelay to the start of a talkspurt of said half rate channels and hencesaid full rate channel than 0123/4567 interleaving.
 10. The system ofclaim 6 , wherein 0246/1357 interleaving is used because of largerresource pools for statistical multiplexing under half duplexconstraints imposed by mobile stations provided for said full ratechannel relative to 0123/4567 interleaving.
 11. A method forcommunicating using wireless time division multiplexed communications inwhich time is divided into a plurality of frames and each frame isdivided into N data bursts, said method comprising the steps of:interleaving bursts using a 0246/1357 sequence to provide a plurality ofhalf rate channels; using two half rate channels on consecutivetimeslots of said plurality of half rate channels to provide a full ratechannel; and transmitting said full rate channel bursts from a firststation to a second station.
 12. A method as set forth in claim 11wherein said transmitting said full rate channel from a first station toa second station step further includes using non-ideal frequency hoppingduring the transmitting.